In the race to pick a candidate to run against Trump, Democrats will grapple with the tension between the party’s establishment and liberal wings that flared during the 2016 state-by-state nominating contests between Hillary Clinton and Bernie Sanders, an independent senator who ran under the Democratic banner.

Elizabeth Warren is among the Democrats running in 2020 – a contest that’s expected to be crowded. Photograph: Justin Wan/AP

Gabbard made headlines in 2016 by quitting a leadership post at the Democratic National Committee over the party’s decision to limit the number of debates between Clinton and Sanders. Analysts believed fewer debates benefited Clinton.

Elizabeth Warren is running – here are 10 others who may seek the Democratic nomination

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Clinton ultimately won the Democratic nomination but lost to Trump.

The congresswoman then endorsed Sanders for president, becoming one of the few members of Congress to do so.